这个都是过去DOS时代的汇编源码，虽然已经过去了，但是对于学习汇编还是有帮助的，汇编语言只是程序员一门基础语言，大多人掌握即可，不一定要深入研究.......
;
; Macro file for MSDOS.
;
SUBTTL BREAK a listing into pages and give new subtitles
PAGE
BREAK MACRO subtitle
SUBTTL subtitle
PAGE
ENDM
BREAK <I_NEED: declare a variable external, if necessary, and allocate a size>
;
; declare a variable external and allocate a size
;
I_NEED MACRO sym,len
CODE ENDS
DATA SEGMENT BYTE PUBLIC 'DATA'
IFIDN <len>,<WORD>
EXTRN &sym:WORD
ELSE
IFIDN <len>,<DWORD>
EXTRN &sym:DWORD
ELSE
EXTRN &sym:BYTE
ENDIF
ENDIF
DATA ENDS
CODE SEGMENT BYTE PUBLIC 'CODE'
ENDM
;
; call a procedure that may be external. The call will be short.
;
invoke MACRO name
&.xcref
add_ext name,near
&.cref
CALL name
ENDM
PAGE
;
; jump to a label that may be external. The call will be near.
;
transfer MACRO name
&.xcref
add_ext name,near
&.cref
JUMP name
ENDM
;
; get a short address in a word
;
short_addr MACRO name
IFDIF <name>,<?>
&.xcref
add_ext name,near
&.cref
DW OFFSET DOSGROUP:name
ELSE
DW ?
ENDIF
ENDM
;
; get a long address in a dword
;
long_addr MACRO name
&.xcref
add_ext name,far
&.cref
DD name
ENDM
;
; declare a PROC near or far but PUBLIC nonetheless
;
procedure MACRO name,distance
PUBLIC name
name PROC distance
ENDM
PAGE
;
; define a data item to be public and of an appropriate size/type
;
I_AM MACRO name,size
PUBLIC name
IFIDN <size>,<WORD>
name DW ?
ELSE
IFIDN <size>,<DWORD>
name DD ?
ELSE
IFIDN <size>,<BYTE>
name DB ?
ELSE
name DB size DUP (?)
ENDIF
ENDIF
ENDIF
ENDM
PAGE
;
; play games with a possible external. Create a new
; macro for the symbol and text, and string it together
; with a central invoker
;
.xcref
.xcref ?i
.xcref def_mac
.xcref ?z0
.xcref add_ext
.cref
IF1
?i=0
ENDIF
?z0 macro
endm
;
; add an external declaration to s with type t if it is not defined
;
add_ext macro s,t
&.xcref
&.xcref ?&s
&.cref
IFNDEF ?&s
?i = ?i + 1
def_mac ?z&%?i,?z&%(?i-1),s,t
ENDIF
endm
;
; define a macro called that possibly externals s:t and then calls macro n
;
def_mac macro m,n,s,t
&.xcref
&.xcref ?&s
&.xcref m
&.cref
m macro
ifndef s
extrn s:&t
endif
purge m
purge ?&s
n
endm
?&s macro
&endm
endm
;
; call the macro chain
;
do_ext macro
&.xcref
expand_mac ?z%?i
&.cref
endm
PAGE
expand_mac macro m
m
endm
;
; define an entry in a procedure
;
entry macro name
PUBLIC name
name:
endm
BREAK <ERROR - print a message and then jump to a label>
error macro code
local a
.xcref
MOV AL,code
transfer SYS_RET_ERR
.cref
ENDM
BREAK <JUMP - real jump that links up shortwise>
;
; given a label <lbl> either 2 byte jump to another label <lbl>_J
; if it is near enough or 3 byte jump to <lbl>
;
jump macro lbl
local a
.xcref
a:
ifndef lbl&_J ; is this the first invocation
JMP lbl
ELSE
IF lbl&_J GE $
JMP lbl
ELSE
IF ($-lbl&_J) GT 126 ; is the jump too far away?
JMP lbl
ELSE ; do the short one...
JMP lbl&_J
ENDIF
ENDIF
ENDIF
endm
BREAK <RETURN - return from a function>
return macro
local a
.xcref
a:
RET
ret_l = a
endm
BREAK <CONDRET - conditional return>
makelab macro l,cc,ncc
j&ncc a ; j<NCC> a:
return ; return
a: ; a:
ret_&cc = ret_l ; define ret_<CC> to be ret_l
endm
condret macro cc,ncc
local a,b
ifdef ret_l ; if ret_l is defined
if (($ - ret_l) le 126) and ($ gt ret_l)
; if ret_l is near enough then
a: j&cc ret_l ; a: j<CC> to ret_l
ret_&cc = a ; define ret_<CC> to be a:
else
makelab a,cc,ncc
endif
else
ifdef ret_&cc ; if ret_<CC> defined
if (($ - ret_&cc) le 126) and ($ gt ret_&cc)
; if ret_<CC> is near enough
a: j&cc ret_&cc ; a: j<CC> to ret_<CC>
ret_&cc = a ; define ret_<CC> to be a:
else
makelab a,cc,ncc
endif
else
makelab a,cc,ncc
endif
endif
endm
;condret macro cc,ncc
; local a,b
; ifdef ret_l ; if ret_l is defined
; if (($ - ret_l) le 126) and ($ gt ret_l)
; ; if ret_l is near enough then
; a: j&cc ret_l ; a: j<CC> to ret_l
; ret_&cc = a ; define ret_<CC> to be a:
; exitm
; endif
; endif
; ifdef ret_&cc ; if ret_<CC> defined
; if (($ - ret_&cc) le 126) and ($ gt ret_&cc)
; ; if ret_<CC> is near enough
; a: j&cc ret_&cc ; a: j<CC> to ret_<CC>
; ret_&cc = a ; define ret_<CC> to be a:
; exitm
; endif
; endif
; j&ncc a ; j<NCC> a:
; return ; return
; a: ; a:
; ret_&cc = ret_l ; define ret_<CC> to be ret_l
;endm
BREAK <RETZ - return if zero, links up shortwise if necessary>
retz macro
condret z,nz
endm
BREAK <RETNZ - return if not zero, links up shortwise if necessary>
retnz macro
condret nz,z
endm
BREAK <RETC - return if carry set, links up shortwise if necessary>
retc macro
condret c,nc
endm
BREAK <RETNC - return if not carry, links up shortwise if necessary>
retnc macro
condret nc,c
endm